Most of the knowledge about syphilis is that it is a type of STD and a common infectious disease. The scientific explanation is that syphilis is a chronic systemic infectious disease caused by the syphilis spirochete. It is transmitted mostly by sexual intercourse . If the disease develops in the form of skin, mucous membrane and internal organs, it is called acquired syphilis. At the same time, mother-to-child transmission is also one of the ways of transmission of syphilis, which is medically known as congenital syphilis. It is similar to the transmission of AIDS. Syphilis is usually contracted through sexual contact, and promiscuity and frequent changes in sexual partners can increase the rate of infection. In addition to sexual intercourse, syphilis can also be contracted through non-sexual contact. For example, if medical personnel are exposed to a patient or pathogen infected with syphilis without any protection, and a susceptible recipient receives blood infected with syphilis, then the recipient can be infected with syphilis under non-sexual conditions; other than that, infection through non-biological is a very rare route of transmission. Syphilis is divided into stage I syphilis, stage II syphilis, and stage III syphilis. The onset of syphilis varies at different times, and the earlier the onset the more severe it becomes at a later stage. Syphilis has an incubation period of three weeks, and the onset of the disease is usually ushered in during the phase I syphilis period after the spirochete has infiltrated. At the beginning, a dark red infiltrate as large as a grain of rice is created at the site of infection, which slowly forms a raised patch after 2 weeks. During this process, other symptoms appear, such as hard chancre symptoms complicating: vesicles, ulcers, and plasma oozing; the beginning of stage II syphilis means that syphilis progresses further to severe conditions, with the spirochete expanding throughout the body with blood circulation, producing a large inflammatory area. The outlook is unpredictable for the more severe symptoms, and for the less severe ones, they subside after a few weeks. Meanwhile the rash in the anus and external genitalia develops vesicles and plasma exudation under the previously mentioned moist and frictional conditions caused by inflammation, a condition known as lichen planus; stage III syphilis is advanced syphilis, and generally at stage III syphilis proves that the condition has reached a fairly critical point. However, stage III syphilis usually develops 4 to 5 years after infection before damage occurs. After entering the third stage of syphilis, syphilis will become syphilis rash and gum-like swelling, when the virus will invade the skin, mucous membranes, bones and other lines of defense of the human body, and in 10 to 20 years can invade the last line of defense of the human immune system, which will damage the cardiovascular and nervous systems and cause aortitis.